CREST syndrome (also known as. limited systemic sclerosis or limited scleroderma) is a variant of progressive systemic sclerosis (PSS) and stands for
C - calcinosis
R - Raynaud phenomenon
E - oesophageal dysmotility
S - sclerodactyly
T - telangiectasia
Critical shoulder angle (CSA) is a parameter, that in some studies 1, correlates with rotator cuff tear (RCT) or glenohumeral osteoarthritis (OA). Some studies 5,6 have shown CSA not associated with RCT.
The CSA measures acromial cover and the inclination of the glenoid, integrating both anato...
The critical zone of the rotator cuff is an area approximately 8-15 mm from the insertion of the rotator cuff tendons onto the greater tubercle of the humeral head, mainly within the supraspinatus tendon. This is a watershed zone between the anterior and posterior circumflex humeral, thoracoacro...
The crossing sign is seen on true lateral plain radiographs of the knee when the line of the trochlear groove crosses the anterior border of one of the condyle trochlea. It is a predictor of trochlear dysplasia. Trochlear dysplasia has been linked to recurrent patellar dislocation 1,2,4. The cro...
The crossover sign, also known as the 'figure of 8' sign, is a plain film sign that indicates acetabular retroversion 2. Acetabular retroversion is a predisposing factor for pincer-type femoroacetabular impingement and is thought to promote hip osteoarthritis 3.
Cross over toe deformity is a type of deformity where one toe may deviate medially or laterally crossing another toe.
It has been reported to be more commonly seen in women over the age of 50 years 1, and in patients with hallux valgus.
It can occur if there is a unil...
Crouzon syndrome is rare disorder characterized by premature craniosynostoses.
abnormal calvarial shape: in severe case can give a "cloverleaf skull"
shallow orbits with exophthalmos
mid facial hypoplasia
It carries an autosomal dominant...
Crowned dens syndrome is an inflammatory condition resulting from crystal deposition in the cruciform and alar ligaments surrounding the dens, appearing as a radiopaque 'crown' surrounding the top of the dens. It typically presents with pain and increased inflammatory markers.
The location of the cruciate ligament insertions onto the femur can be remembered with the mnemonic:
AE: anterior onto external condyle
PI: posterior onto internal condyle
The cruciate ligament of the atlas (also known as the cruciform ligament) is an important ligamentous complex that holds the posterior dens of C2 in articulation at the median atlantoaxial joint. It lies behind a large synovial bursa (surrounded by loose fibrous capsule) and consists of two band...
Crystal arthropathies are a group of joint disorders due to deposition of crystals in and around joints which lead to joint destruction and soft tissue masses.
The most common arthropathies are:
gouty arthropathy due to monosodium urate (MSU) deposition
pseudogout due to calcium py...
The C sign is an important radiological sign which may be seen on a lateral radiograph of the ankle in those with the talocalcaneal subtype of tarsal coalition.
A continuous C-shaped arc on a lateral ankle radiograph is formed by the medial outline of the talar dome an...
CT guided bone biopsy is a type of image guided biopsy.
It may be performed using the 'CT fluoroscopy' capabilities of modern CT scanners or with the traditional step-wise approach.
CT biopsies are usually performed using a co-axial needle technique to gain a stable position through which the ...
The cubital fossa (a.k.a. antecubital fossa) (plural: fossae) is an inverted triangular space that forms the transition between the arm and the forearm. It is located anterior to the elbow joint.
The terms cubital/antecubital fossa are also used in surface anatomy for the skin overlying this re...
The cubital tunnel is a space through which the ulnar nerve passes posterior to the medial epicondyle of the humerus.
cubital tunnel retinaculum (also known as ligament or band of Osborne), extends from the olecranon to the medial epicondyle
Cubital tunnel syndrome is a type of ulnar nerve compression neuropathy due to pathological compression of the ulnar nerve along its course within the cubital tunnel.
The compression of the ulnar nerve at the elbow is the second most common peripheral neuropathy of the upper extre...
Cubitus varus (gunstock deformity) is a malalignment of the distal humerus that results in a change of carrying angle from the physiologic valgus alignment (5-15 degrees) of the arm and forearm to varus malalignment. Historically, it is a complication of supracondylar fractures with a frequency ...
The cuboid bone is one of the tarsal bones located lateral to the lateral cuneiform bone and has an important articulation with the calcaneus.
The cuboid is a wedge shaped bone, being widest at its medial edge and narrow at its lateral edge. It has three main articular...
Cuboid syndrome is a cause of lateral midoot pain, believed to result from abnormal articulation of the cuboid with the calcaneus (calcaneocuboid joint).
Cuboid syndrome presents with lateral foot pain and swelling, often diffuse and similar to an ankle (ligament) sprain ...
Currarino-Silverman syndrome, also known as pectus carinatum type 2 deformity, is a rare disorder.
Patients present with a high carinate chest deformity due to a premature fusion of the manubriosternal joint and sternal ossification centers. Congenital heart diseases have...
The curtain sign, also known as the draped curtain sign, in neuroimaging refers to the appearance of a vertebral body mass that extends posteriorly towards the anterior epidural space.
The posterior longitudinal ligament is strongly attached to the posterior vertebral body cortex in the midline...
Cutaneous and subcutaneous metastases are not uncommon, occurring in ~5% (range 0.7-10.4%) of internal malignancies, and representing 2% of skin cancers. The Sister Mary Joseph nodule is a well known cutaneous metastasis.
These metastases can come from haematogenous or lymphatic spre...
Cutis laxa is a rare dermatological condition, characterized by elastic fiber loss, resulting in very lax skin. Patients can also develop emphysema.
Cutis laxa may be inherited (autosomal dominant, autosomal recessive, or X-linked recessive) or may occur sporadically.
A cyamella is a rare sesamoid bone that exists as a normal variant within the popliteus tendon, characteristically located at the lateral aspect of the distal femur in the popliteal groove.
Cyamella is best seen on the AP view of plain radiograph as opposed to fabella, which is best appreciated...
The cyclops lesion, also known as localized anterior arthrofibrosis, is a painful anterior knee mass that arises as a complication of anterior cruciate ligament (ACL) reconstruction, although has rarely been reported in patients with ACL injuries that have not been reconstructed.
A cyma line refers to the union of two curved lines in architecture. In a radiological context it refers to the smooth joining of the midtarsal joint lines of the talonavicular and calcaneocuboid joints on both AP and lateral views.
A disruption of the cyma line can indicate true shortening of ...
Cyriax syndrome, also known as slipping rib syndrome, occurs when hypermobility of the rib cartilage of the lower ribs slips and moves, leading to pain in lower chest or upper abdomen 1.
This condition may occur at any age, but is reportedly more common in middle-aged adults, and ...
Cysticercosis is a parasitic tissue infection caused by ingestion of tapeworm eggs through a fecal-oral transmission or auto-infection. Humans act as a definitive host in this disease.
CNS manifestations are discussed individually on neurocysticercosis.
The disease is endemic in ...
The musculoskeletal manifestations of cystic fibrosis are uncommon compared to the well known respiratory manifestations.
For general discussion of cystic fibrosis, and a discussion of its other manifestations, please refer to:
cystic fibrosis (parent article)
pulmonary manifestations of cys...
Cystic synovial hyperplasia is a form of synovial hyperplasia which has several cystic components.
May be seen as a multi-cystic synovial proliferative lesion.
T1 C+: less intense peripheral enhancement only.
on MR imaging it can mimic a syn...
There is broad differential for cyst-like lesions around the knee.
popliteal synovial cyst - Baker cyst
intra-articular ganglion cyst
ACL ganglion cyst
PCL ganglion cyst
Hoffa fat pad ganglion cyst
extra-articular ganglion cyst
The dagger sign is a radiographic feature seen in ankylosing spondylitis as a single central radiodense line on frontal radiographs related to ossification of the supraspinous and interspinous ligaments secondary to enthesitis.
The Dameron-Lawrence-Botte classification, or Lawrence-Botte classification, is a commonly used nomenclature for proximal fifth metatarsal fractures, which are categorized into one of three anatomic zones of involvement:
zone 1: tuberosity (styloid process) avulsion fracture
Danon disease is an X-linked dominant cause of debilitating cardioskeletal myopathy and is a lysosomal storage disorder.
Although considered rare, the exact incidence is unknown 1.
Danon disease is characterized by the triad of 1-4:
Decompression sickness (DCS), also known as diver's disease, aerobullosis, the bends or caisson disease, is an uncommon diving-related decompression illness that is an acute neurological emergency typically occurring in deep sea divers.
Decompression sickness can be furt...
A dedifferentiated chondrosarcoma is a combined tumor made up to two components which are often sharply demarcated from one another (thus raising the possibility of it representing a collision tumor).
conventional chondrosarcoma (low grade)
dedifferentiated high grade areas
malignant fibrous ...
Deep bursae are those bursae that are located deep to the fibrous fascia and are normally located between muscles or muscle and bone. These bursae form in utero alongside synovial joint formation 1.
In contrast, superfical bursae are located superficial to the fibrous fascia.
The deep peroneal (fibular) nerve is one of two terminal branches of the common peroneal nerve.
origin: the terminal branch of common peroneal nerve in the lateral compartment of the leg
course: passes into the anterior compartment of the leg, where it courses inferiorly into the dors...
The deep posterior compartment of the leg is one of the four compartments in the leg between the knee and foot. Muscles within this compartment primarily produce ankle plantarflexion and toe flexion, with exception of the popliteus which acts on the knee. Of the two posterior compartments, the d...
The deep sulcus sign can refer to two different radiographic signs but is best known in the chest:
deep sulcus sign (chest): of pneumothorax on supine CXR:
deep sulcus sign (knee): better known as the lateral femoral notch sign of ACL injury
Degenerative disc disease (DDD) is an exceedingly common entity in the spine, encountered with increasing frequency throughout life and becoming almost universal in late adulthood to a varying degree. It is related to a combination of biomechanical stresses and genetic predisposition which alter...
Degloving injuries can refer to a number of conditions:
degloving soft tissue injury
Morel-Lavallée lesion (closed degloving soft tissue injury)
intramuscular degloving injury
degloving bowel injury
Degloving soft tissue injuries can be extensive and quite severe conditions. These may be open or, less commonly, closed injuries, which are known as Morel-Lavallée lesions. This article focuses on open injuries, with closed injuries discussed in the Morel-Lavallée article.
Dehiscence is a general term referring to 'splitting open' and is used in a variety of contexts in medicine generally and radiology more specifically.
The two most common usages are:
splitting open of a wound (e.g. sternal dehiscence)
loss of bone separating one structure from another (e.g. ...
A generalized retardation in skeletal maturation has different causative or etiological factors, these can be classified as follows:
chronic ill health
congenital heart disease (especially cyanotic)
chronic renal disease
inflammatory bowel disease
malnutrition: failure to thrive (FTT)
Delayed onset muscle soreness (DOMS) refers to the muscular pain and swelling that follows unaccustomed exertion.
Patients may have an ache in affected muscles with reduced strength 4.
DOMS is thought to occur from reversible microstructural muscle injury that...
The Delbet classification helps predict the risk of avascular necrosis of the femoral head in neck of femur fractures, as well as determine operative vs non-operative management.
type I: trans-epiphyseal separation
fracture through proximal femoral physis, and represents Salte...
Deltoid ligament injuries involve the deltoid ligament that forms the medial part of the ankle joint. It attaches the medial malleolus to multiple tarsal bones.
Mechanism of injury
It occurs due to eversion and/or pronation injury, or can be associated with lateral ankle fractures.
The complex of the medial collateral ligaments of the ankle joint is collectively called deltoid ligament. It attaches the medial malleolus to multiple tarsal bones.
The ligament is composed of two layers. The superficial layer has variable attachments and crosses two joints whil...
The deltoid muscle (also known as deltoideus muscle) is the largest of the shoulder muscles. The muscle is composed of three heads (clavicular, acromial and spinous), although electromyography suggests that there are at least seven control regions that could act independently 1.
The deltopectoral groove is located between the superolateral aspect of the pectoral region and the deltoid muscle. It runs obliquely from superomedial to inferolateral and contains the cephalic vein which at the upper margin of the groove dives deep to pierce the clavipectoral fascia and enter ...
Denervation changes in muscles can be observed in a number of settings.
in the very early stage, muscle signal may be normal
earliest change is increased T2 signal (best seen on a fat saturated T2WI such as STIR)
chronic changes are marked by muscle atrophy and fat...
The differential diagnosis for a dense base of the skull includes:
Van Buchem disease
The differential diagnosis of dense metaphyseal bands is wide.
chronic anemia, e.g. sickle cell disease, thalassemia
chemotherapy, e.g. methotrexate
growth acceleration lines following growth arrest due to systemic illness or stress in infancy or childhood, e.g...
Common causes of dense transverse metaphyseal lines can be remembered using the mnemonics:
D: D-vitamin intoxication
E: elemental arsenic and heavy metals (lead, bismuth, phosphorus)
N: normal variation
S: systemic illness
E: estrogen to mother ...
Densitometric vertebral fracture assessment (VFA) is an image of the lumbar and thoracic spine acquired on dual energy x-ray absorptiometry (DXA) scanners, for the purpose of diagnosing osteoporotic vertebral fractures.
The technique is available on DXA scanners under a variety of...
Depressed skull fractures result in the bone of the skull vault being folded (depressed) inward into the cerebral parenchyma. It is usually the result of a high energy impact to the skull.
These mostly (~75%) occur in the frontoparietal region 3.
There are a number of ...
De Quervain tenosynovitis, also known as washerwoman's sprain/strain, is a painful stenosing tenosynovitis involving the first extensor (dorsal) tendon compartment of the wrist (typically at the radial styloid). This compartment contains the abductor pollicis longus (APL) and extensor pollicis b...
Dercum disease, also known as adiposis dolorosa, is a rare disorder of subcutaneous tissue characterized by multiple painful lipomas.
Although the exact incidence is unclear, Dercum disease affects women more than men 1,2. It is usually sporadic, however, autosomal dominant forms ...
Dermatofibrosarcoma protuberans (DFSP) is a low-grade malignant tumor arising from dermal and subcutaneous tissues and is the most common cutaneous sarcoma (although overall still quite rare). It is most commonly found at the trunk and proximal extremities 6.
Its behavior is notable for a high ...
Dermatographia, also known as skin writing, refers to a skin condition in which skin scratches causes linear red marks. The cause is unknown, however, it is related to penicillin use and mastocytosis.
Dermatomyositis is an autoimmune inflammatory myositis, which like its closely-related condition polymyositis, carries an increased risk of malignancy.
There is a recognized female predilection. It has a bimodal age of presentation depending on the variant:
A derotational screw is an orthopedic device used for internal fixation of fractures to, unsurprisingly, limit rotation of the fracture.
They are applied across fractures at risk of rotation and hence avascular necrosis.
Describing a bone lesion is an essential skill for the radiologist, used to form an accurate differential diagnosis for neoplastic entities, and occasionally non-neoplastic. In addition to patient demographics, the radiographic features of a bone lesion are often the primary determinant of non-h...
Describing a fracture is a basic requirement when making an assessment of a plain radiograph. There are many ways to approach the assessment of the radiograph; this is just one approach.
I: Describe the radiograph
What radiograph (or radiographs) are you looking at? Check the who, what, why, w...
Desmoid tumors are benign, non-inflammatory fibroblastic tumors with a tendency for local invasion and recurrence but without metastasis.
The terms desmoid tumor and aggressive fibromatosis are occasionally used synonymously by some authors 9. This article will focus on the abdomin...
Desmoplastic fibromas are extremely rare bone tumors that do not metastasize but may be locally aggressive. They are considered to be a bony counterpart of soft tissue desmoid tumors and are histologically identical.
Incidence is ~0.3%. The most common areas of involveme...
Developmental dysplasia of the hip (DDH), or in older texts congenital dislocation of the hip (CDH), denotes aberrant development of the hip joint and results from an abnormal relationship of the femoral head to the acetabulum.
Unlike CDH, developmental dysplasia of the hip is not confined to c...
dGEMRIC, or delayed gadolinium-enhanced MRI of cartilage is a technique that can be used quantitatively to assess glycosaminoglycan content of cartilage or qualitatively to asses the overall structures of cartilage. When the technique is adapted and applied to menisci it is called dGEMRIM.
Diabetic myonecrosis is an uncommon complication of diabetes mellitus, occurring in patients with chronic poor glycemic control.
There is a slight predilection for females and patients with type 1 diabetes. The average age of presentation is 40 years.
Diaphragmatic eventration refers to an abnormal contour of the diaphragmatic dome. It typically affects only a segment of the hemidiaphragm, compared to paralysis/weakness where the entire hemidiaphragm is typically affected.
Diaphragmatic eventration is congenital in nature and due...
Diaphragmatic paralysis (also considered very similar to the term diaphragmatic palsy) can be unilateral or bilateral.
Clinical features are highly variable according to underlying etiological factor:
unilateral paralysis: asymptomatic in most of the patients as the othe...
Diaphyseal lesions are unsurprisingly predominantly found centered in the diaphysis.
simple bone cyst
myeloma / plasmacytoma
round cell tumor, e.g. Ewing sarcoma (children)
A mnemonic for a short list of diaphyseal lesions is:
C: bone cysts
E: enchondroma/Ewing sarcoma
M: bone metastasis
E: eosinophilic granuloma
N: non-ossifying fibroma (NOF)
The diaphyses (singular: diaphysis), sometimes colloquially called the shafts, are the main portions of a long bone (a bone that is longer than it is wide) and provide most of their length.
The diaphysis has a tubular composition with a hard outer section of hard cortical bone and a central po...
Diarthroses are a functional class of joint that are freely mobile. All synovial joints are considered diathroses.
Diastasis recti (rectus diastasis) or divarication of the recti is a stretching of the linea alba with abnormal widening of the gap between the two medial sides of the rectus abdominis muscle (increased inter-recti distance).
The degree of widening needed for the diagnosis is controversial, wit...
Diastrophic dysplasia (DTD) is a type of short limb skeletal dysplasia (micromelic dwarfism). Adult patients have a stature between 100 and 140 cm.
There may be a relatively increased prevalence in Finland ref.
Typically there is limb shortening, hitchhiker thu...
Die-punch fractures result from an axial loading force on the distal radius. It is an intra-articular fracture of the lunate fossa of the distal radius 1. It is by definition depressed or impacted and is named after the machining technique of shearing a shape, depression or hole in a material wi...
The difference in vertical mid-vertical angle is the difference in the vertical mid-vertebral angle (VMVA) between the caudal segment angle and the adjacent cephalad segment angle of the three most caudal segments of the lumbar spine as measured on a mid-sagittal MRI or a lateral radiograph.
Forefoot pain in the metatarsal region is a common complaint and may be caused by a number of conditions. It is worthwhile for a radiologist to have knowledge of the potential causes and their imaging features 1.
plantar plate disruption
Useful mnemonics for remembering causes of diffuse bony sclerosis include:
3 M's PROOF
Regular Sex Makes Occasional Perversions Much More Pleasurable And Fantastic 1
3 M's PROOF
metastases (osteoblastic metastases)
Diffuse idiopathic skeletal hyperostosis (DISH), also referred to as Forestier disease, is a common condition characterized by bony proliferation at sites of tendinous and ligamentous insertion of the spine affecting elderly individuals. On imaging, it is typically characterized by the flowing o...
A diffuse homogeneous bone marrow FDG uptake usually reflects hyperplastic bone marrow which can be seen in the following conditions:
granulocyte colony-stimulating factor (G-CSF)
Diffuse T1 vertebral bone marrow signal loss is associated with replacement of fatty marrow by edema or cellular tissue. T1-weighted imaging without fat suppression is one of the most important sequences for distinguishing between normal and abnormal bone marrow. In the case of homogenous involv...
A dinner fork deformity, also known as a bayonet deformity, occurs as the result of a malunited distal radial fracture, usually a Colles fracture. The distal fragment is dorsally angulated, displaced and often also impacted. The term is descriptive, as the lateral view of the wrist is similar to...
A direct inguinal hernia arises from protrusion of abdominal viscera through a weakness of the posterior wall of the inguinal canal medial to the inferior epigastric vessels, specifically through the Hesselbach's triangle.
This type of hernia is termed direct as the hernial sac directly protrud...
The term disarticulation refers to the disconnection of all or part of a limb from the body, specifically through a joint. This is in contrast to amputation, which is the disconnection or removal of the structure through a bone.
Discal cysts (also known as a disk cyst or disc cyst) are uncommon lesions of the spine, representing an extrathecal cyst which communicates with the adjacent intervertebral disc through an annular fissure.
The vast majority of discal cysts, as rare as they are, have been reporte...
A disc bulge represents displacement of the outer fibers of the annulus fibrosus beyond the margins of the adjacent vertebral bodies, involving more than one-quarter (25% or 90 degrees) of the circumference of an intervertebral disc 3. Because it is limited by the annulus fibrosus it does not ex...
Disc desiccation (also known as disc dehydration) is an extremely common degenerative change of intervertebral discs. The incidence climbs with age, and to a large degree a gradual dehydration is a 'normal' part of disc aging. It results from replacement of the hydrophilic glycosaminoglycans wit...
Disc extrusion is a type of intervertebral disc herniation and is distinguished from a disc protrusion in that it:
in at least one plane, has a broader dome (B) than a neck (A)
extends above or below the disc level (into the suprapedicular or infrapedicular zone)
Disc extrusions are a...
Disc herniation refers to the displacement of intervertebral disc material beyond the normal confines of the disc but involving less than 25% of the circumference (to distinguish it from a disc bulge). A herniation may contain nucleus pulposus, vertebral endplate cartilage, apophyseal bone/osteo...